Beta-propiolactone modification of wool



United States PatentO I 1 2,717,194 BETA-PROPIOLACTONE MODIFICATION OF WOOL William Gordon Rose and Harold P. Lundgren, Berkeley, Calif., assignors to the United States of America as represented by the Secretary of Agriculture No Drawing. Application October 21, 1954,

Serial No. 463,837 I 4 Claims. (Cl. 8-112) (Granted under Title 35, U. S. Code (1952), sec. 266) A non-exclusive, irrevocable, royalty-free license in the invention herein described, for all governmental purposes, 1

aforesaid reaction is carried out in the presence of a high molecular weight alcohol whereby the rate of beta-propiolactone uptake by the wool is increased. Further objects and advantages of the invention will be obvious from the description herein.

It has been shown by Lundgren, Rose, and Jones (U. S. Patent No. 2,672,397) that wool reacts with beta-propiolactone to produce a chemically modified wool which has many advantages over the untreated wool, particularly, the modified wool forms felts of greater tensile strength than those produced from the natural wool. Further, the modified wool forms a felt more rapidly than does the natural wool. In carrying out this-known process, the beta-propiolactone dissolved in a solvent such as carbon tetrachloride, chloroform, methanol, ethanol, etc. is applied to the wool. Water is also added to the solution (or to the wool) to act as a promoter thus to accelerate the rate of reaction.

It has now been found that the reaction between wool and beta-propiolactone is enhanced by the presence of high-molecular weight aliphatic alcohols, that is, aliphatic alcohols containing at least eight carbon atoms. The

action of high-molecular weight alcohols in this regard is surprising particularly since beta-propiolactone is not soluble in these alcohols so that there is no possibility that the effect of these alcohols is due to solvent action. It has been determined that when the wool modification treatment is carriedout in the-presence of a high-molecular weight alcohol, the uptake of beta-propiolactone is 30% to 40% higher than where the treatment is in the presence of a solvent such as carbon tetrachloride and the reaction time is the same. The marked effect of the high-molecular weight alcohols in accelerating the wool modification reaction is demonstrated in the examples below.

As the high-molecular weight alcohol one may use various compounds, for example, octyl alcohol, nonyl alcohol, decyl alcohol, undecyl alcohol, dodecyl alcohol, tridecyl alcohol, tetradecyl alcohol, pentadecyl alcohol, hexadecyl alcohol, heptadecyll alcohol, octadecyl alcohol, octenyl alcohol, nonenyl alcohol, decenyl alcohol, undecenyl alcohol, dodecenyl alcohol, tridecenyl alcohol, tetradecenyl alcohol, pentadecenyl alcohol, palmitolcyl alcohol, oleyl alcohol, ricinoleyl alcohol, and so forth.

In general, the reaction of wool with beta-propiolactone in accordance with this invention is conducted at a temperature from about C. to about 100 C. Preferably, a temperature below about 40." C. is'used to promote actual reaction of the wool with the lactone and to minimize polymerization of the lactone in the treatment bath or on the surface of the wool fibers. Usually, for convenience, the reaction is conducted at about room temperature.

In any case the high molecular alcohol should be applied in a liquid condition. This may require, for example, heating of the reaction mixture if the particular Patented Sept. 6, 1955 2 alcohol selected is normally a solid. Mixtures of the alcohols may be used to form a composite material which will be liquid at a temperature lower than the melting point of the alcohol ingredient having the higher melting point. Thus a normally solid alcohol like palmityl alcohol can be maintained in liquid condition at room temperature by mixing it with octyl alcohol, oleyl alcohol or other normally liquid alcohol. Also the high molecular weight alcohol can be liquefied by dissolving it in a solvent suchas chloroform, carbon tetrachloride, ethylene dichloride, ether, benzene, acetone, hexane, petroleum ether, Stoddard solvent, gasoline or a low molecular weight alcohol such as methanol, ethanol, propanol, iso- "propanol, any of the isomeric butyl or amyl alcohols, etc.

For best results the medium, that is, the solution of the high molecular weight alcohol in the solvent, should contain at least about 10% of the high molecular weight alcohol.

In carrying out the process of this invention the wool to be treated is intimately'contacted with beta-propiolactone and the medium containing the high-molecular weight alcohol. Usually the medium is used in large excess so that the wool will be completely immersed therein. The beta-propiolactone is also applied in excess to promote a high degree of lactone uptake by the wool. Generally at least one part of beta-propiolactone is used per part of wool, preferably about 10 parts of lactone per part of wool is applied to ensure complete reaction. The unreactedportion ofthe lactone can be recovered from the reaction mixture and re-used.

The medium containing the high-molecular weight a1- coholshould also contain about 1 to 15% water, preferably bout 4, to 8% water, to promote reaction between the wool and lactone. It has also been observed that instead of water methyl alcohol can be applied to obtain this promoting effect. Howevenvmethyl alcohol is not as etfective as waterand hence water is the preferred reagent. The. use of methyl alcohol in this respect is demonstrated inExample III hereinafter.

The time of reaction depends on many factors such as the particular high-molecular weight alcohol used in the medium,thepercentageof water (or methanol) in the medium, the temperature and degree of uptake of lactone desired. Ingeneral it is preferred to allow the reaction to continue until the wool has taken up about 30 to about 70% propiolactone, based .on the weight of dry wool. .Chemically modified fibers of this type possess optimum properties for felting. For other purposes, the time of reaction, or other conditions may be adjusted to obtain a greater or lesser degree of chemical modification.

After the reaction of the wool with the lactone and other reactants has been carried out, the chemically modified wool is mechanically treated as by wringing, centrifuging, or the like to remove excess reagents. Residual beta-propiolactone, lactone hydrolysis products, etc. are then removed by washing with an inert solvent such as carbon tetrachloride, ethylene dichloride, benzene, acetone, ethanol, etc. Inm'any cases it is also preferred to wash themodified wool with water or an aqueous solution of a weak or moderately alkaline material such as sodium bicarbonate, sodium carbonate, borax, etc. to remove any beta-hydroxypropionic acid or other materials If an The following examples demonstrate the invention in greater detail. It is understood that these examples are furnished by way of illustration and not limitation.

EXAMPLE I A series of experiments was carried out employing the following technique in each case: One gram of dry wool was placed in a vessel together with ml. of beta-propiolactone, 40 ml. of dodecyl alcohol and a measured quantity of water (as set forth below). The vessel containing the wool and other ingredients was shaken thoroughly then allowed to stand at 25 C. for hours. The wool was then removed, washed successively with carbon tetrachloride, ethanol, water and then dried at 105 C. The uptake of beta-propiolactone was calculated by the increase in weight of the wool sample. The results obtained are set forth below.

Percent of water in waterdodecyl alcohol mixture Uptake of betapropiolactone by the wool, percent F o-Jo @Ulcq COMPARATIVE EXPERIMENTS The following experiments are not illustrative of the invention but are included in order to show the inferior results obtained when using various solvents in place of highmolecular weight alcohols.

A series of experiments was carried out using the following technique in each case: one gram of dry wood was placed in a vessel together With 10 ml. of beta-propiolactone, 40 ml. of solvent (carbon tetrachloride, toluene, or hexane) together with a measured quantity of water. The vessel containing the wool and other ingredients was shaken thoroughly then allowed to stand at C. for 20 hours. The wool was then removed, washed successively with the same solvent as used in the reaction, ethanol, water, and then dried at 105 C. The uptake of beta-propiolactone was calculated by the increase in weight of the wool sample.

It is to be noted that in these trials, the proportions of water used with each solvent covered the range at which maximum uptake of beta-propiolactone was obtained for the particular solvent. Thus for example in the case of carbon tetrachloride, proportions of water of 0.42% to 7.0% give maximum uptake of propiolactone; proportions of water outside this range give lesser uptakes of the lactone. The same holds for the other solvents with the proviso that in each case the range of proportion of water giving maximum lactone uptake is difierent.

The results obtained are set forth below.

Table 2.Reaction of wool with beta-propiolactone in the presence of various solvents 4 EXAMPLE n The procedure of Example I was repeated except that A in this case instead of dodecyl alcohol there were used oleyl alcohol and 3,9-diethyltridecanol-6, respectively.

The results obtained are set forth below:

Table 3.Reucti0n of wool with beta-propiolactone in the presence 0] oleyl alcohol and 3,9-dz'ethyltridecanol-6 Two experiments were carried out employing the following technique in each case: One gram of dry wool was placed in a vessel together with 10 m1. of beta-propiolactone, 40 ml. of dodecyl alcohol and a measured quantity of methanol (as set forth below). In this case no water was present; all the reactants were essentially anhydrous. The vessel containing the wool and other ingredients was shaken thoroughly then allowed to stand at 25 C. for 20 hours. The wool was then removed, washed successively with carbon tetrachloride, ethanol, water and then dried at C. The uptake of beta-propiolactone was calculated by the increase in weight of the wool sample. The results are set forth below:

Table 4.Reaction of wool with beta-propiolactoue in the presenceof dodecyl alcohol and methanol Percent of Uptake of methanol belta-t me ano proplo ac one Sample dodecyl by the alcohol wool, mixture percent l of a liquid medium at least 10% of which is dodecyl References Cited in the file of this patent UNITED STATES PATENTS 2,517,573 Jones et a1. Aug. 8, 1950 OTHER REFERENCES Fearnley et al.: The Action of B-Propiolactone on Wool, J. Soc. Dyers & Colourists, March 1952, pp. 88-91.

Lundgren et al Mar. 16, 1954 p 

1. A PROCESS FOR CHEMICALLY MODIFYING WOOL COMPRISING REACTIONG WOOL WITH BETA-PROPIOLACTONE IN THE PRESENCE OF A LIQUID MEDIUM AT LEAST 10% OF WHICH IS A HIGH-MOLECULAR WEIGHT ALIPHTIC ALCOHOL CONTAINING AT LEAST 8 CARBON ATOMS. 